Note: Descriptions are shown in the official language in which they were submitted.
CA 02739009 2015-01-21
1
Apparatus and method for transporting flexible, planar
products
The present invention relates to an apparatus and a
method for transporting flexible, planar products.
In particular in mailrooms of printing houses, the
printed products are frequently transported by means of
gripper conveyors. In this context, it frequently
happens that the printed products are delivered from
the gripper conveyors to the belt conveyor for further
processing. In the case of large processing capacities
and the high conveying velocities associated therewith,
the problem exists that the printed products flap when
transferred from the gripper conveyor to the belt
conveyor and, in particular, behave erratically after
being released by the grippers of the gripper
conveyors, with the risk of losing their ordered
arrangement.
An object of the present invention is therefore to
provide an apparatus and a method for transporting
flexible, planar products, which apparatus/method
ensures a secure and reliable transfer of the products
from a gripper conveyor to a belt conveyor, even at
high conveying velocities.
The grippers of the gripper conveyor are designed to,
with their gripper jaw, hold and transport a flexible,
planar product, in particular a printed product such as
a newspaper, a magazine or the like, by its holding
region, which lies contiguous to a holding edge. Since
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the products are secured in the gripper jaw, they have
a precisely defined position. According to the
invention, the motional path of the gripper jaws, i.e.
of the free end of the gripper jaws, has in a transfer
portion, in which the products are transferred from the
gripper conveyor to a belt conveyor, an arc-shaped
course. Preferably, the course is arc-shaped over the
whole of the transfer portion.
The grippers can respectively be loaded with a single
product. It is also possible, however, for the grippers
to be loaded with more than one product, for example
two products, these products being arranged in an
imbricated formation, so that the holding regions of
the products are exposed.
According to the invention, the belt conveyor is
configured as a vacuum belt conveyor having a
perforated belt, the active strand of which runs in the
transfer portion at a distance to the motional path of
the gripper jaws.
The arc-shaped course of the motional path of the
gripper jaws leads to a secure bearing contact of the
products, with their free end region facing away from
the holding edge, against the active strand of the
vacuum belt conveyor. The vacuum belt conveyor suctions
the end region of the particular products to the active
strand, whereby said products are stabilized and held
in a defined position, so that, when the particular
grippers are subsequently opened, they can no longer
alter this position.
Since the motional path of the gripper jaws has an arc-
shaped course and the active strand of the vacuum belt
conveyor runs in the transfer portion at a distance to
the motional path, the mutual spacing of the products,
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or the overlapping thereof, is also altered in the
course of the transfer. If the arc-shaped course of the
motional path is convex, the distance between the free
end edges of successive products, which free end edges
lie opposite the holding edges of the products, is
increased. Correspondingly, this distance is reduced in
the case of a concave course.
Vacuum belt conveyors have at least one self-contained
perforated belt, which is driven such that it rotates
in the direction of conveyance and the holes of which,
in the suction portion of the active strand, are
connected to a vacuum source. The suction portion can
here extend around virtually the entire length of the
active strand. It is also possible, however, for the
suction portion to be divided, in the direction of
conveyance, into successive sub-portions.
Usually, vacuum belt conveyors are provided with a
vacuum pan, which is connected to the vacuum source and
over whose opening the active strand of the perforated
belt is moved. The holes of the perforated belt which
are respectively located in the region of the opening
are hence connected to the vacuum source.
The gripper jaws have in the transfer portion a speed -
measure of their vectorial velocity - which, according
to the invention, is less than the speed - and thus the
rotational velocity - of the perforated belt.
Preferably, the active strand has in the transfer
portion an at least approximately arc-shaped course
which is equidirectional to the motional path. An at
least approximately arc-shaped course means that the
arc can be imitated also by successive, chord-like
portions.
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In a preferred embodiment of the apparatus according to
the invention, the motional path of the gripper jaws
has in the transfer portion, and preferably over the
entire length of the transfer portion, a circular-arc
shaped course. The distance between the products, or
their free end edges, in the transfer portion hence
remains at least approximately constant.
Preferably, the distance between the motional path of
in the gripper jaws and the active strand of the vacuum
belt conveyor is adjustable. The optimal processing of
printed products of different thickness and different
length is thereby made possible.
In a further preferred embodiment of the apparatus
according to the invention, the clamping tongues of the
grippers, which respectively form a gripper jaw, and
thus the gripper jaws per se, are mounted pivotably
about a gripper axis running transversely, in
particular at right angles, to the direction of
conveyance. This makes it possible, for example by
means of a link motion, to control the desired pivotal
position of the gripper jaws upon reaching the transfer
portion, and within this. More particularly, the
gripper axis runs parallel to the conveying surface
defined by the vacuum belt conveyor.
Preferably, the gripper jaws, upon reaching the
transfer portion and within the transfer portion, are
directed obliquely rearward with respect to the
direction of conveyance. The free end edge of the
products is hence trailing with respect to their
holding edge located in the gripper jaw.
Preferably, the gripper conveyor has a conveying member
guided in a guide channel. This is preferably in the
form of a link chain, which is capable of withstanding
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tensile and compressive load. On the conveying member,
cantilever-like carrying members are arranged at a
predetermined carrier spacing, which carrying members
reach through the gap of the guide channel of C-shaped
cross section. These carrying members respectively
carry, outside the guide channel, a gripper. In such an
embodiment, the exact position and location of each
product, and thus the location of the products relative
to one another, is always predefined and known.
In a preferred embodiment of the apparatus according to
the invention, in the transfer portion the motional
path of the gripper jaws is convex and,
correspondingly, the active strand of the vacuum belt
conveyor is concave. This embodiment allows the
centrifugal forces to be utilized, which force the free
end region of the products into bearing contact against
the active strand of the vacuum belt conveyor.
If, in such an embodiment, the motional path of the
gripper jaws, in the transfer portion, is located
radially on the outside with respect to the conveying
member to which the grippers are fastened by carrying
members, the distance between the free end edges of the
successive products in relation to the carrier spacing,
and thus to the distance which these end edges adopt in
a rectilinear course of the gripper conveyor, is
additionally increased.
Preferably, the active strand is divided in the
transfer portion into rectilinear segments, which
succeed one another in the direction of conveyance, and
thus forming chords of the arc, allow a concave course
of the active strand in the transfer portion. This
embodiment offers the possibility, between successive
segments, of holding the perforated belt radially to
the outside with respect to the arc.
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At least some of the segments are assigned a vacuum
pan, which is connected to a vacuum source and over
which runs the active strand. At least those segments
which are located in the suction portion of the vacuum
belt conveyor are configured in this way. Preferably,
all - possibly apart from the first or the last
segment, viewed in the direction of conveyance - are
realized in this way.
Preferably, the perforated belt is guided between
respectively successive segments in a Q shape around
deflexion rollers. This allows a low-friction
operation.
Moreover, the perforated belt is preferably shored in
the region of the vacuum pans, by means of supporting
rollers, against the movement into the vacuum pans.
In a further preferred embodiment of the apparatus
according to the invention, the vacuum belt conveyor
has, in addition to the perforated belt, at least one
further perforated belt driven at the same speed,
preferably one on each of the two sides. The segments
of the further perforated belt or belts are preferably
arranged offset, in the direction of conveyance, in
relation to the segments of the perforated belt, so
that the region between successive segments of the
perforated belt is bridged by a segment of the further
perforated belt or belts. Uninterrupted holding of the
end regions of the products, despite segmentation of
the active strand, is thereby ensured.
In the transfer portion, the motional path of the
gripper jaws can be shaped concavely and the active
strand of the vacuum belt conveyor correspondingly
convexly. A rectilinear course of the active strand is
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also conceivable. In these embodiments, segmentation of
the vacuum belt conveyor is unnecessary.
It should be mentioned that the distance between the
motional path of the gripper jaws and the active strand
of the vacuum belt conveyor prevents the formation of a
nip for the products. The transfer portion is thus
nipless. The distance is greater than the thickness of
the products and, should these overlap, greater than
the overall thickness of the overlapping products.
In the method according to the invention, a flexible,
planar product is transported by means of a gripper
conveyor into a transfer portion. To this end, the
product is secured, by a holding region of the product,
in the gripper jaw of grippers arranged one behind
another. The grippers arranged one behind another are
driven rotatingly in a direction of conveyance F. The
product transported into the transfer portion is in
this portion, in an end region facing away from its
holding region, suctioned by an active strand, driven
in the direction of conveyance F, of a perforated belt
of a vacuum belt conveyor. After the product, in its
end region, has been suctioned to the active strand of
the vacuum belt conveyor, the grippers of the gripper
conveyor open and the product is transported onward by
means of the vacuum belt conveyor. The active strand
here runs at a distance A to the motional path of the
gripper jaws. The motional path of the gripper jaws has
an arc-shaped course. The perforated belt is driven at
a belt speed which is greater than the speed at which
the gripper jaws are driven.
In a preferred embodiment of the method, in the
transfer portion the active strand runs in the same
direction as the motional path of the gripper jaws and
at least approximately in an arc shape.
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In a further preferred embodiment, the motional path of
the gripper jaws in the transfer portion runs in the
shape of a circular arc.
In a further preferred embodiment of the method, the
motional path of the gripper jaws runs convexly and the
active strand of the vacuum belt conveyor runs
concavely.
The invention is explained in greater detail with
reference to an illustrative embodiment represented in
the drawing, wherein, purely schematically:
fig. 1 shows in a perspective, oblique top view
a part of an apparatus according to the
invention, comprising a gripper conveyor,
which transports printed products to a
transfer portion, and an evacuation conveyor,
which in the transfer portion is configured
as a vacuum belt conveyor to take up and
carry off the supplied printed products;
fig. 2 shows in the same representation as fig.
1 that region of the apparatus which is shown
there, without printed products;
fig. 3 shows in perspective representation from
obliquely above the rear side of that region
of the apparatus which is shown in figs. 1
and 2;
fig. 4 shows in the same
perspective
representation as figs. 1 and 2 three
mutually adjacent perforated belts of the
vacuum belt conveyor, with corresponding
vacuum pans;
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fig. 5 shows in perspective representation the
middle perforated belt of the vacuum belt
conveyor, with associated vacuum pans;
fig. 6 shows in side view the middle perforated
belt, with the associated vacuum pans;
fig. 7 shows in top view one of the outer
perforated belts of the vacuum belt conveyor,
with associated vacuum pans;
fig. 8 shows in a section along the line VIII-
VIII of fig. 7 the perforated belt which is
shown there, with the corresponding vacuum
pans;
fig. 9 shows in perspective representation the
perforated belt, with the associated vacuum
pans, according to figs. 7 and 8;
fig. 10a shows, in heavily simplified representation,
a first example of a path course of the
gripper jaws of the gripper conveyor and of
the evacuation conveyor;
fig. 10b shows the speed ilnr1 of the perforated belt and
the speed Ivi of the gripper jaws in
dependence on the location;
fig. lla shows, in heavily simplified representation,
a second example of a path course of the
gripper jaws of the gripper conveyor and of
the evacuation conveyor;
fig. lib shows, once again, the speed Iwi of the
perforated belt and the speed ivi of the
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gripper jaws in dependence on the location;
and
fig. 12 shows
the angular velocity and the
velocities v and w or the speeds ivi and iwi
at a point on the respective path course.
Fig. 1 shows a region, relating to the present
invention, of an apparatus for transporting flexible,
planar products 10, in the present case printed
products such as newspapers, magazines or the like. It
has a gripper conveyor 12, serving as a feed conveyor,
whose grippers 14, which are driven rotatingly in a
direction of conveyance F and are arranged one behind
another, are designed to, with their gripper jaw 16,
respectively secure a product 10 by its holding region
18 adjoining a holding edge 20 and transport it to a
transfer portion 22.
Arranged downstream of the gripper conveyor 12 is an
evacuation conveyor 24 configured as a belt conveyor,
which in the transfer portion 22 is configured as a
vacuum belt conveyor 26. The vacuum belt conveyor 26,
which is disposed in the transfer portion 22 beneath
the gripper conveyor 12, is designed to, in the
transfer portion 22, with its active strand 28 of the
perforated belt 30, which active strand 28 is driven in
the direction of conveyance F, suction the products 10,
held by the gripper conveyor 12, in their end region 32
facing away from the holding edge 20 and, following
subsequent release by the grippers 14, transport them
onward. The release takes place close to the
downstream-situated end 34 of the transfer portion 22
and the vacuum belt conveyor 26 conveys the received
products 10 to a belt conveyor 36 of the evacuation
conveyor 24, which belt conveyor 36 is arranged
downstream of the first-named conveyor in the direction
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of conveyance F and is provided with parallel conveyor
bands.
The motional path 38 of the gripper jaws 16 has in the
transfer portion 22 an arc-shaped course, in the
illustrative embodiment represented in the drawing a
circular-arc-shaped course which is convex with respect
to the self-enclosed gripper conveyor. The vacuum belt
conveyor 26 is arranged radially on the outside with
respect to the arc of the gripper conveyor 12 such that
the active strand 28 in the transfer portion 22 has an
at least approximately constant distance A to the
motional path 38.
Each gripper 14 has two interacting clamping tongues 40
forming the gripper jaw 16, one of the clamping tongues
40, in the present case the leading one viewed in the
direction of conveyance F, determining the pivotal
position of the grippers 14 and thus of the gripper jaw
16, and the other, trailing clamping tongue 40 being
pivoted relative to the leading clamping tongue 40 for
the opening and closing of the gripper jaw 16.
The motional path 38 is given by the movement of the
free end of the clamping tongue 40 defining the
position of the grippers 14, in the shown illustrative
embodiment of the leading clamping tongue 40.
At this point it should be noted that the distance A
between the motional path 38 and the vacuum belt
conveyor 26 is greater than the thickness of the
products 10 to be conveyed, and should these overlap,
as in the shown illustrative embodiment, greater than
the overall thickness of the products 10 in the region
of overlap. The products 10 are thus, in the transfer
portion 22, not held in a nip.
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In particular, embodiments as are known, for example,
from printed publications EP 0 600 183 Al, EP 0 557 680
Al and EP 0 557 679 Al are suitable as grippers 14. The
clamping tongues 40, which respectively form a gripper
jaw 16, can be pivoted relative to one another about a
gripper axis 42 running at right angles to the
direction of conveyance F and parallel to the conveying
surface defined by the vacuum belt conveyor 26 and, in
the closed setting of the gripper jaw 16, are locked
under spring load by means of a locking lever 44, see
fig. 3.
One of the clamping tongues 40, in the present case the
one which is leading in the direction of conveyance F,
is fixedly connected to a positioning follower roller
46, which is guided in a positioning link 48 to control
the rotational position of the grippers 14 and thus of
the gripper jaw 16.
The other one of the clamping tongues 40, in the shown
illustrative embodiment the one which is trailing in
the direction of conveyance F, is connected by a spring
to a closing lever 50, which on the one hand bears a
follower roller 52, mounted such that it is freely
rotatable, and, on the other hand, is designed to
interact with the locking lever 44; see fig. 3.
For the closing of the grippers 14, or of the gripper
jaw 16, the follower roller 52 is moved by means of a
closing link (not shown) such that the clamping tongue
connected by the spring to the closing lever 50 is
pivoted toward the other clamping tongue 40 held in its
position by the positioning follower roller 46 and the
positioning link 48, to be precise to the point where,
35 following the bearing contact of the clamping tongues
40 one against another, or against a product 10
arranged therebetween, the spring is tensioned and the
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closing lever 50 is interlocked with the locking lever
44 for the generation of the clamping force. For the
opening of the grippers 14, close to the end 34 of the
transfer portion 22, the locking lever 44 is pivoted by
means of an opening apparatus 54 such that it releases
the closing lever 50 and the clamping tongue 40
connected thereto can move into the opening setting.
The structure and the working method of such grippers
14 is explained in detail in the aforementioned printed
publications and the pertinent disclosure should
herewith be integrated into the present description.
For the sake of completeness, it should be mentioned
that the opening apparatus 54 is arranged such that it
opens the grippers 14 which are respectively moved past
it, if the clamping tongue 40 which determines the
motional path 38 is close to the downstream-situated
end 34 of the transfer portion 22.
Each of the grippers 14 is fastened in a known manner
to a cantilever-like carrying member 56. The carrying
members 56, for their part, are fastened with a
predetermined carrier spacing to a self-enclosed
conveying member 58, which is preferably formed by a
link chain capable of withstanding tensile and
compressive load. The conveying member 58 is guided in
a guide channel 60 of C-shaped cross section, the
carrying members 56 reaching through the gap 62 of the
guide channel 60, so that the grippers 40 are outside
the guide channel 60; in the shown illustrative
embodiment, with respect to the arc-shaped course,
radially outside the guide channel 60.
Viewed in the direction of conveyance F, the guide
channel 60, which in the shown region of the apparatus
according to the invention extends in a vertical plane,
runs vertically downward, then in a 90 circular-arc
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portion 61 through the transfer portion 22, the end 34
of the transfer portion 22 being followed by a short
rectilinear portion 64. This leads the conveying member
58 tangentially up to a continuously driven deflexion
and drive wheel 66 mounted on a horizontal axis. In an
upward vertical direction, the deflexion and drive
wheel 66 is followed, in turn, by a rectilinear portion
68 of the guide channel 60. The deflexion and drive
wheel 66 driven in the rotational direction D drives
the conveying member 58 and thus the grippers
rotatingly in the direction of conveyance F.
The grippers 14 are aligned in their pivotal position
by means of the positioning link 48 such that, upon
reaching the transfer portion 22 and up to the end 34
thereof, the gripper jaws 16 are directed obliquely
rearward with respect to the direction of conveyance F.
Hence, the holding edges 20 of the products 10, with
respect to the end edges 32' situated opposite them,
are leading, and in the transfer portion 22 the holding
edges 20, viewed in the radial direction, are located
further in than the end edges 32' and the thereto
adjoining end region 32.
In the shown illustrative embodiment, in the transfer
portion 22, the pivotal position of the grippers 14 is
maintained with respect to the direction of conveyance
F, so that the motional path 38 runs at a constant
distance to the guide channel 60 and thus, in the
transfer portion 22, has a circular-arc-shaped course.
It should be mentioned that the gripper conveyor 12 is
assigned guide rods 70, which at a fixed distance to
the guide channel 60 and to the motional path 38,
viewed in the direction of conveyance F, extend as far
as the vacuum belt conveyor 26. The products 10 held by
the grippers 40 slide with their end region 32 along
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these guide rods 70, which ensure that the products 10
maintain their obliquely rearward running, possibly
curved position, as represented in fig. 1, also in the
vertically downward running portion and during
standstill of the gripper conveyor 12.
The vacuum belt conveyor 26 is realized so as to be
vertically adjustable in order to be able to adjust the
distance A between the motional path 38 and the active
strand 28, in dependence on the thickness of the
products 10 to be processed.
The vacuum belt conveyor 26 has at least one self-
enclosed perforated belt 30, which is driven such that
the active strand 28 moves in the direction of
conveyance F at a rotational velocity and thus belt
speed lwi which is greater than the speed Iv( of the
gripper jaws 14. Preferably, for the gripper jaws 14
and the active strand 28, the angular velocity co, in
the transfer portion 22, is at least approximately
equal.
If a single perforated belt 30 is provided, this is
arranged preferably symmetrically to the plane in which
the motional plane 38 extends. If two perforated belts
are provided, one of the perforated belts 30 is
preferably located on each side with respect to this
plane. Particularly preferably, the vacuum belt
conveyor 26 is configured as represented in figs. 2 and
30 3, with a perforated belt 30 in the middle and, on each
side of this perforated belt 30, a further perforated
belt 30' .
The active strand 28 of the centrally arranged
perforated belt 30 is formed by four rectilinear, at
least approximately equally long segments 72, which
follow on from one another in the direction of
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conveyance F and which are arranged at angles to one
another and, forming chords, imitate the concave arc.
Viewed in the direction of conveyance F, the second,
third and fourth segments 72 are respectively assigned
a vacuum pan 74, as is described in greater detail
further below. The first segment 72 thus serves
exclusively for the guidance of the end regions 32 of
the products 10, while the second, third and fourth
segments 72 form a suction portion 76 of the active
strand 28 of the perforated belt 30.
In the shown illustrative embodiment, the active strand
28 extends over an angle of about 40 .
The two further perforated belts 30' arranged to the
side of the perforated belt 30 form in the region of
the active strand 28, in a similar manner to the
perforated belt 30, rectilinear segments 72', which
succeed one another in the direction of conveyance F
and are arranged at angles to one another in order,
forming chords of the arc, likewise to imitate the
concave course. The first and last segments 72', viewed
in the direction of conveyance F, are configured
roughly half as long as the particular segments 72 of
the perforated belt 30, while the further three
segments arranged between these segments 72' have
roughly the same length as the segments 72 of the
perforated belt 30.
The segments 72' of the further, likewise self-enclosed
perforated belts 30' thus bridge the short gaps between
the segments 72 of the perforated belt 30, and the
segments 72 correspondingly bridge the short gaps
between the successive segments 72' of the further
perforated belts 30' .
As is additionally described further below, the middle
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three segments 72' of the further perforated belts 30
are respectively assigned a vacuum pan 74' . The suction
portion 76' of the active strand 28 of the further
perforated belts 30' thus lies in the region of the
middle three segments, while the respectively first
segment 72' and last segment 72', viewed in the
direction of conveyance F, serve for the guidance of
the end regions 32 of the products 10.
The suction portion 76" of the vacuum belt conveyor 26
- see also fig. 4 - formed by a combination of the
suction portions 76 and 76' of the first perforated
belt 30 and of the further perforated belts 30', thus
extends, viewed in the direction of conveyance F, from
approximately the middle of the first segment 72 of the
perforated belt 30 to toward the end of the last
segment 72 of this perforated belt 30.
The vacuum belt conveyor 26 is directly followed, in
the direction of conveyance F, by the belt conveyor 36,
which, in the shown illustrative embodiment, has four
conveying bands 78, which are arranged side by side and
are driven at the same velocity as the perforated belts
30, 30' .
In fig. 4, the centrally arranged perforated belt 30
and the two perforated belts 30' arranged to the side
thereof, with the associated drive rollers 80 and
deflexion rollers 82, as well as the vacuum pans 74,
74' assigned to the particular segments 72, 72', are
shown in perspective representation. The machine frame
provided with a casing - compare figs. 1 to 3 - on
which the drive rollers 80, deflexion rollers 82 and
the further rollers mentioned further below are mounted
and to which the vacuum pans 74, 74' are fastened, is
not represented.
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The endless perforated belt 30 - see also fig. 5 - and
the endless further perforated belts 30' - compare also
figs. 7 and 9 - are provided with a continuous hole
pattern, so that a multiplicity of continuous suction
holes 84 are always present in the region of the vacuum
pans 74, 74' . In the present case, the perforated belts
30, 30' are provided with transverse rows of suction
holes 84, which rows are arranged successively one
behind another in the direction of rotation U, a
plurality of such rows respectively being located in
the region of each vacuum pan 74, 74' .
Both the perforated belt 30 and the further perforated
belts 30' are guided at the upstream-situated end
around deflexion rollers 82, which are mounted
coaxially in a freely rotatable manner, and at the
downstream-situated end around drive rollers 80, which
are likewise coaxially mounted, yet are connected to
one another and to a drive motor M - see figs. 6 and 8.
Between two respectively successive segments 72, 72',
the perforated belts 30, 30' are respectively deflected
in a Q-like manner around three further deflexion
rollers 86, which have parallel axes, are arranged in
the isosceles triangle and are mounted such that they
are freely rotatable. Two of these three further
deflexion rollers 86, viewed in the direction of
conveyance F, are respectively arranged directly one
after the other, the upstream-situated one of these
further deflexion rollers 86 being arranged close to
the downstream-situated end of a segment 72, 72' and
the adjacent deflexion roller 82 being arranged at the
upstream-situated end of the following segment 72, 72'.
The third of these further deflexion rollers 86 is
arranged such that it is offset, with respect to the
two others, downward in the direction of the return
strand 88.
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The return strand 88 of each perforated belt 30, 30' is
guided adjacent to the particular drive roller 80 and
adjacent to the associated deflexion roller 82 in an S-
shape around a roller pair 90 in order, on the one
hand, to increase the angle of wrap about the drive
roller 80 or deflexion roller 82 and, on the other
hand, to increase the distance of the return strand 88
to the active strand 28 and make space for the vacuum
pans 74, 74' arranged therebetween. Roughly midway
between these roller pairs 90, the perforated belt 30
and the further perforated belts 30' are guided around
a respective tensioning roller 92 in order to keep the
perforated belts 30, 30' taut. Acting between the
machine frame and the tensioning rollers 92 is a
respective tension spring 94, see figs. 6 and 8.
The vacuum pans 74, 74' are connected by a piping 96 to
a commonly known vacuum source (not shown). On the side
facing the active strand 28, the vacuum pans 74, 74'
are open and the perforated belt 30 or the particular
further perforated belt 30' runs over this opening. The
suction holes 84 respectively located in the region of
these openings are connected to the vacuum source.
The vacuum pans 74, 74' each have a planar flange 98,
which encircles the opening and protrudes radially
outward, which flanges, on the one hand, support the
active strand 28 and, on the other hand, prevent false
air from being sucked into the vacuum pans 74, 74' . For
the sake of completeness, it should be mentioned that
the width of the openings of the vacuum pans 74, 74' is
less than the width of the associated perforated belt
30, or of the further perforated belt 30'.
In the shown illustrative embodiment, the width of the
further perforated belts 30' is greater than the width
of the perforated belt 30. Preferably, the vacuum pans
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74' assigned to the further perforated belts 30' are
provided with supporting rollers 100, mounted in a
freely rotatable manner, to prevent the particular
regions of the further perforated belts 30' from being
sucked into the vacuum pans 74'. As can be deduced, in
particular, from fig. 8, each particular vacuum pan 74'
can be assigned, for example, three supporting rollers
100, which extend over at least a part of the width of
the opening of the vacuum pans 74' and are seated in a
freely rotatable manner on bearing shafts, which latter
extend at right angles to the direction of conveyance F
and direction of rotation U through the vacuum pans 74'
and are fastened to the side walls thereof. The
supporting rollers 100 can be narrowly configured, so
that they rather form supporting wheels. Naturally, it
is also possible to arrange a plurality of narrow
supporting rollers 100 or supporting wheels side by
side on a bearing shaft. It is also conceivable, of
course, to provide supporting rollers 100 in the vacuum
pans 74 assigned to the perforated belt 30.
The radius with which the guide channel 60 is curved in
the transfer portion 22 can measure, for example, about
500 mm. The deflexion and drive wheel 66 can have a
radius of, for example, 250 mm. On the conveying member
58, the carrying members 56 are arranged, for example,
with a center-to-center spacing of 100 mm. Furthermore,
the grippers 24 can be controlled in their pivotal
position such that the motional path 38 in the transfer
portion 22 has a radius of about 600 mm. If the
distance between the motional path 38 of the gripper
jaws 16 and the active strand 28 of the vacuum belt
conveyor 26 here amounts to a distance A of about 75
mm, the products 10 are taken up by the gripper
conveyor 12 with a distance of 135 mm between the end
edges 32' of successive products 10 and carried off in
the direction of evacuation W. In the rectilinear
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portions of the motional path 38, this distance
amounted to 100 mm.
If, based on the above-specified dimensions, the
conveying member 58 is driven at a rotational velocity
of, for example, 1000 mm/s, the gripper jaws 16 move at
a speed Ivi of 1200 mm/s and the active strand 28 moves
at a speed 1141 (and rotational velocity) of 1350 mm/s.
The motional path 38 runs in the transfer portion 22
preferably in the shape of a circular arc, the radius
of the circular arc for the processing of printed
products preferably being chosen less than one meter.
The length of the transfer portion 22 measures, for
example, between 300 mm and one meter, preferably about
500 mm.
In fig. 10a, the course of the motional path 38 of the
gripper jaws is shown in heavily simplified
representation, the direction of conveyance being
denoted by F. In the shown example, the course of the
motional path 39 of the active strand of the perforated
belt of the vacuum belt conveyor is rectilinear. The
course of the motional paths 38 and 39 is here divided
into an inlet portion I, a transfer portion II and an
outlet portion III. The inlet portion I refers to that
part of the motional paths 38 and 39 which leads to the
transfer portion II. The outlet portion III refers to
that part of the motional paths 38 and 39 which leads
away from the transfer portion II. Radii of curvature
102 and 103 of the motional path 38 of the gripper jaws
in the transfer portion II and in the outlet portion
III respectively are likewise shown. As can be seen
from fig. 10b, in the transfer portion II the active
strand of the perforated belt is driven at a speed 1141
which is greater than the speed ivi of the gripper jaws.
In the outlet portion III, a sharp increase in speed ivi
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occurs due to the smaller radius of curvature 103.
In fig. 11a, a further example of the course of the
motional path 38 of the gripper jaws is shown, once
again, in heavily simplified representation. The
direction of conveyance is denoted by F. In the shown
example, the course of the motional path 39 of the
active strand of the perforated belt of the vacuum belt
conveyor is concavely curved. The course of the
motional paths 38 and 39 is here divided into an inlet
portion I, a transfer portion II and an outlet portion
III. The inlet portion I once again refers to that part
of the motional paths 38 and 39 which leads to the
transfer portion II. The outlet portion III refers to
that part of the motional paths 38 and 39 which leads
away from the transfer portion II. The radii of
curvature 104, 105 and 106 are likewise shown. As can
be seen from fig. 11b, in the transfer portion II the
active strand of the perforated belt is driven at a
speed iwt which is greater than the speed )vi of the
gripper jaws. In the outlet portion III, a sharp
increase in speed Ivi occurs due to the smaller radius
of curvature 106.
Fig. 12 illustrates the relationship between the
angular velocity and the velocities v and w or the
speeds Ivi and lwi at a point on the respective path
course. Here too, it can be seen that, at the
respectively shown point (blackened circle) on the
motional paths 38 and 39, the speed pwl of the
perforated belt is greater than the speed tvi of the
gripper jaws on the motional path 38.
The working method of that embodiment of the apparatus
according to the invention which is shown in the
figures is as follows. The grippers 14 are continuously
driven such that they rotate in the direction of
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conveyance F. The grippers 14 are each loaded in a
loading station with a product 10, the grippers 14,
with their gripper jaw 16, respectively grasping the
product 10 in its holding region 18 contiguous to the
holding edge 20, and securing the same. The grippers 14
are supplied to the transfer portion 22 with a pivotal
position such that that free end edge 32' which lies
opposite the holding edge 20, and thus the thereto
adjoining end region 32, viewed in the direction of
conveyance F, is trailing with respect to the holding
edge 20. In the direction of the transfer portion 22,
the products 10 slide with their end region 32 along
the guide rods 70 and then, aided by the centrifugal
forces and as a result of the convex course of the
motional path 38 of the gripper jaws 16, come to bear
with their end region 32 against that active strand 28
of the vacuum belt conveyor 26 which lies radially on
the outside with respect to said motional path 38.
In the region of the first segments 72, 72' of the
vacuum belt conveyor 26, the end regions 32 of the
products 10 are extensively supported, whereby they
stabilize. In the adjoining suction portion 76", the
end regions 32 are suctioned to the perforated belt 30
and the further perforated belt 30' and are thereby
secured. At the end 34 of the transfer portion 22, the
grippers 14 which run past there are respectively
opened, whereby the particular products 10 are
released. Since they are held at this moment by the
vacuum belt conveyor 26, they cannot alter their
position to the perforated belt 30, 30' and relative to
one another. The products 10 are held stable when their
holding region 18 is released. Despite an airstream, a
stable delivery of the products 10 onto the vacuum belt
conveyor 26 with a defined altered spacing between the
holding edges 20 of successive products 10 is realized.
The stabilized products 10 are released from the vacuum
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belt conveyor 26 close to the downstream-situated end
of the suction portion 76 and are carried off in an
ordered formation by means of the downstream belt
conveyor 36.
The length of the transfer portion 22, measured in the
direction of conveyance F, is greater than the extent
of the largest products 10 to be transported. The width
of the suction-active region of the vacuum belt
conveyor 26, measured at right angles to the direction
of conveyance F, is chosen smaller than the width of
the, in this regard, smallest products 10 to be
transported.
